Several x--ray pulsars exhibit line structure in their spectra that has been
interpreted as originating from cyclotron processes when the radiation scatters
from plasma electrons embedded in a strong magnetic field.
A few of these objects also show evidence of a second spectral feature that,
traditionally, has been thought to be the second cyclotron harmonic. We present
detailed calculations of emitted flux spectra for x--ray pulsars that incorporate
a two--component model of the accretion cap. The two components are modeled
as slabs separated by a shock wave where the post--shock slab is the subsonic high density
and temperature plasma that creates the radiation via free--free or bremstrahlung
processes and the pre--shock material is represented by a relatively cool low
density plasma that is moving near the free--fall velocity. We find that two spectral features
are easily produced; one representing the fundamental cyclotron harmonic of the
post--shock plasma; and another that is a Doppler shifted line produced by scattering
in the pre--shock plasma. Our models include the effects of angle--dependent Doppler shift and
aberration. We demonstrate the effect for a range of plasma parameters
and compare our results to observations.